Abstract: An adjustable lumbar support assembly for a seat has a curved lumbar support member that is made from a plastic material and an adjustment mechanism operatively connected to the curved lumbar support member for adjusting between various degrees of curvature. The curved lumbar support member may include a plurality of reinforcing ribs that allow a greater degree of curvature adjacent one end of the element than the degree of curvature adjacent the other end of the element. The reinforcing ribs allow for varying degrees of curvature because the cross section of the ribs varies. Further, the reinforcing ribs are integral with the curved lumbar support member. The adjustable lumbar assembly could also include at least one resilient metal strap connected to the curved lumbar support member that allows a greater degree of curvature adjacent one end of the curved lumbar support member than the degree of curvature adjacent the other end of the element.

Abstract: An apparatus for adjusting the arching of a resiliently flexible support element (4) for supporting the pelvic and/or lumbular vertebrae in a back rest of a seat including an arching mechanism comprising a spring and an operating mechanism. According to the invention the spring (20, 35; 21, 38) is included in the force transmission tract for adjusting the arching. Preferably a spring (20, 35) is fitted between one end of the support element (4) and the force transmission member of the arching mechanism and/or a spring (21, 38) is fitted to the free end of the force transmission member of the arching mechanism behind the operating mechanism.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.